The basis of most use of computers is the creation of files
containing text which may be plain text, computer programs or text with
some mark-up language like TEX. To create and maintain such files one
needs programs called editors. The two most popular editors that are
available on a variety of platforms are vi and emacs. In
addition these editors are versatile enough that one can emulate most
other editors using the framework provided.

The vi editor is provided along with most vendor distibuted
Unix-like systems. However, the GNU project has an editor called Elvis
which is compatible with vi and has many additional features. This is
an ideal editor for programmers and administrators.

A more general purpose editor is emacs which was created
by Richard Stallman-the founder of the GNU project. It is an extremely
versatile editor with a large number of configuration files and added
packages. Many users familiar with emacs start and end their interactions
with the computer with it. It has detailed (hypertext) help and
information within it called the info-mode. One can argue that no
editor which you can buy is better than GNU Emacs--which can be
obtained for free.

A number of other editors are also available in the public archives
like Origami (a folding editor) and Micro-Emacs (a clone of Emacs).
In fact any user can find an editor to his/her liking among the
editors available in the archives or find a configuration of vi/emacs
that suits the purpose.